Tension member for composite construction.



No. 816,334. PATBNTED MAR. 7; 1906.

TENSION MEMBER FOR COMPOSITE CONSTRUCTION,

APPFIGATION FILED JUNE 21, 1905.

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JULIUS KAHN, DETROIT, MICHIGAN, Assrenon To. rnus snn oonennrn errant COMPANY, or n'nrsorr, MICHIGAN, con- PoRA-rron or MICHIGAN.

TENtiQi i WiEit'lEE Pi' FOR COMPOSETE CONSTRUCTION.

. Specification of Letters I-atent.

Patentedmarch v27, 1906 1'0 alt w/tom it may concern:

Be it known that I, J ULIUS KAHN, a citizen of the United States, residing at Detroit, in the county of Wayne and State of Michigan, have invented a new and Improved Tension Member for Composite Constructions, of which the following is a specification.

This invention relates to tension members for combined steel and concrete beams, trusses, and other structures subject to transverse stresses; and the object of my improvement is to provide a tension member of this kind in the form of a rod or bar which shall have pro'ections formed thereon to insure more er ec't engagement between the metal and t e plastic material, while at the same time the tensional strength of the tension member shall be uniform throughout its length. I attain this object by the construetion illustrated in the accompanying drawings, in which Figure 1 is a side view, and Fig. 2 is an edge view, of one form of my improved tension members. Fig. 3 and Fig. 4 are side views of other forms of the same. Fig. 5 is a crosssection on the line A A of Fig. 3. Fig. 6 is a cross-section on the line B B of Fig. 4.

Similarreference characters refer to like parts throughout the several views.

Tension members for concrete steel construction have been formed by twisting an-' gular metal bars, by securing washers and other projections upon the tension-bars intermediate their length at regular intervals, by corrugating the bars, and by forming. r0-

jections on the bars by rolling. T ese changes in the form of the metal are to prevent the bars from slipping in the plastic material when the structure is loaded; but each of the various forms requires an excess of metala portion that serves merely to prevent the slipping of the bar in the concrete and does not carry its proportion of the tensional stress. In my improved construction I have endeavored to so proportion the various parts that the stress required to rupture the metal will be equally great at every point in the length of the bar.

'ing a symmetrical bar.

In Figs. 1 and 2 the bar 1 is provided with a series of projections 2 and 3 on both sides of the bar, those on one side being equal and opposite to those on the other. .The pro'ections 3 are of e ual length, and their width is one-half that of the projections 2, thus form- The projections are beveled at their ends, and the inclines of the projections 3 lap those of projections 2, which is sufficient to cause the amount of metal which would be broken should the line of breakage extend around between the projections to be equal to that should the break be at right angles to the bar.

In Figs. 3 and 5 a bar is shown with projections 4 and 5 and grooves between the same so proportioned that the cross-sectional area is constant for all planes at right angles to the bar. The tensional strength of the bar will therefore be uniform throughout its length.

In Figs. 4 and 6 a bar 6 is shown having a continuous projection 7 on each side in the form of a sinuous ridge, whichridgesmay be symmetrical on the bar, as indicated by the solid and dotted lines of Fig. 4, or they may be opposite each other.

-Many other modifications embodying m invention maybe produced by those skilled in the art, either with continuous or disconnected projections, the point to be attained being that the metal be soproportioned that the bar be of uniform tensile strength, thus avoiding all waste of material, and that the projections be sufl icient to insure good union between the metal and concrete. c

Having now explained my improvements, what I claim as my invention. and desire to secure by Letters Patent, is

1.. A metal bar having a plurality of rows of disconnected projections extending from a side thereof, the projections of one row overlapping the gaps in each adjacent row, the projections being so proportioned that the bar shall be uniform in tensile strength throughout the portion of its length having such projections.

2. A metal bar having a plurality of rows l of disconnected projections extending from each side thereof, the projections of each row In testimony whereof I have signed this having parallel sides, the projections of one application in the presence of two subscribrow overlapping the gaps in each adjacent ing Witnesses. row, and the projections being so propor- 4 JULIUS KAHN;

5 tioned that the bar shall be of uniform ten- Witnesses:

sile strength throughout the portion of its ANNA M. GREGORY, length having suchpiojection's. EDWARD N. PAGELSEN 

